This invention relates to the repair or reinforcing of walls, and more particularly to an apparatus and method for reinforcing a wall constructed of hollow concrete blocks.
A number of prior art systems are known for reinforcing a block wall. Two such systems are shown in McCoy, et al U.S. Pat. No. 4,706,428 and Achtenberg, et al, U.S. Pat. No. 4,563,852.
In the system shown in the McCoy, et al patent, a flexible reinforcing member such as a chain is inserted into a vertical passage formed by the hollow cores in consecutive courses of blocks. The upper end of the chain is fixed to an eye bolt, which has its threaded portion extending upwardly through a plate provided atop the wall. The lower end of the chain extends through an opening formed in the bottom face of the wall just above the floor slab. A plate is positioned over the opening in the face of the block wall, and the chain is fixed to the plate by means of a pin. Tension is then introduced into the chain by turning a nut threaded onto the upwardly extending threaded portion of the eye bolt. There is no connection of the chain to the foundation.
Achtenberg, et al discloses a reinforcing method in which an anchor bolt is inserted into the foundation internally of the block wall, and a reinforcing cable is then fastened to the anchor bolt. An upper opening is formed at the top of the wall, and a top bolt is placed internally of the wall so that its upper end projects above the top plate. The upper end of the steel cable is then fixed to the top bolt. Tension is introduced by turning down a nut provided on the top bolt.
The present invention is intended to provide a reinforcing apparatus and method for a concrete block wall in which a single opening is formed in the wall, and in which the anchor for the lower end of the reinforcing member is secured to the foundation exteriorly of the wall. In a preferred embodiment, the portion of the floor adjacent the bottom of the wall is removed and the anchor is secured to the foundation at the removed portion of the floor. After securing the anchor to the foundation, the floor is patched. With this construction, there is no showing on the wall of any reinforcing apparatus contained therein.
In accordance with the invention, an apparatus for reinforcing a block wall comprises an elongated reinforcing member adapted for placement within a vertical passage in the wall. Anchor means is provided for anchoring the lower end of the reinforcing member, with the anchor means being disposed exteriorly of a face of the wall and toward the bottom of the wall above the foundation. Means is provided for interconnecting the anchor means with the foundation exteriorly of the wall. Retainer means maintains the upper end of the reinforcing member in position. The retainer means is disposed toward the top of the wall and is connected to the upper end of the reinforcing member. Tensioning means is provided for tensioning the reinforcing member after the lower end of the reinforcing member is anchored to the anchor means and the upper end of the reinforcing member is connected to the retainer means. The introduction of tension into the reinforcing member reinforces the wall. The anchor means prevents upward movement of the reinforcing member when tension is introduced thereinto. In a preferred embodiment, the reinforcing member comprises a multi-link chain. The lower end of the chain preferably protrudes through an opening formed in the face of the wall adjacent the foundation. The anchor means preferably includes an upstanding portion adapted for placement against the face of the wall adjacent the opening formed therein. The upstanding portion of the anchor means preferably includes a passage and slot arrangement by which the chain is anchored to the anchor means. The anchor means further preferably includes a base portion which, in a preferred embodiment, is placed against an upwardly facing surface of the foundation where a portion of the floor slab typically placed thereabove has been removed. Fasteners, such as anchor bolts, extend between the base portion of the anchor means and the foundation for securing the anchor means to the foundation. The upstanding portion of the anchor means preferably includes a laterally extending projection adapted for placement in the opening through the wall and extending therethrough, for guiding the chain through the opening and preventing the chain from bearing on the portion of block adjacent the opening.
The invention further contemplates a method of reinforcing a block wall substantially in accordance with the above-noted summary of the reinforcing apparatus. In accordance with the method, the elongated reinforcing member is placed in one of the passages in the wall such that its lower end extends through an opening formed in the face of the wall and toward the bottom of the wall. Anchor means is provided, and the lower end of the reinforcing member is connected to the anchoring means. The anchoring means is then secured to the foundation. Retaining means is provided for maintaining the upper end of the reinforcing member in position, and tension is then introduced into the reinforcing member for reinforcing the wall. A floor slab is typically placed above the foundation at the bottom of the wall, and the method preferably contemplates removal of a portion of the floor slab adjacent the bottom of the wall. In this manner, the anchoring means can be placed directly onto the upper surface of the foundation and secured thereto. After the wall has been reinforced in accordance with the above-described steps, the removed portion of the floor can then be replaced so as to cover the anchoring means. Accordingly, there is no evidence on the exposed portion of the wall that the wall has been reinforced.